1. Field of the Invention
This disclosure relates to semiconductor packages and, more particularly, to a high-power ball grid array (BGA) package having a heat spreader, a method for manufacturing the heat spreader, a BGA printed circuit board (PCB) to which the method is applied, and a method for manufacturing the BGA PCB.
2. Description of the Related Art
As devices become highly integrated, the number of connection pads in a semiconductor device, such as a semiconductor memory device, increases. Thus, the number of lead lines in a package included in a PCB also increases. As the number of lead lines increases, a lead frame using conventional package technology cannot be applied to a highly-integrated semiconductor chip having over 400 lead lines. Accordingly, a BGA package has been introduced in which package output terminals are arranged on a large bottom board of the package.
The BGA package includes a square-shaped main body, a semiconductor chip which is mounted on the top surface of the main body, and matrix solder balls at the bottom surface of the main body that contact the printed circuit board and thus can be arranged and mounted on a pad of the printed circuit board by using a reflow process.
Such a BGA package requires a heat spreader on the surface of the semiconductor chip so as to emit heat to the outside the package when a considerable amount of heat is generated during the operation of the semiconductor chip. However, since a gold wire is formed upwardly to connect the semiconductor chip with the pad of the main body of the package, it is difficult to mount the heat spreader on the BGA package and so such BGA package is not appropriate for a high-power BGA package.
Referring to FIG. 12, illustrated is a conventional, high-power BGA package structured to overcome the heat emitting problem of the conventional BGA package described above. The conventional high-power BGA package includes a package printed circuit board 1200, a through portion 1200a at the center of the package circuit board 1200, pads for bonding (not shown) at the bottom surface of the printed circuit board 1200, a heat spreader 1110 that is connected to the top surface of a metal layer 1120, a supporting main body 1130 that is connected to the bottom surface of the heat spreader 1110, and a semiconductor chip 1101 that is mounted under the supporting main body 1130 within the through portion 1200a, includes a plurality of metal pads 1101a on its bottom surface, and is connected to pads for the bonding (not shown) and gold wires 1101b. This conventional high-power BGA package is capable of easily emitting heat away and cooling the semiconductor chip through the heat spreader 1110 that is stably mounted on the surface of the BGA package, even though the heat is generated in the semiconductor device.
The heat spreader 1110 of the conventional high-power BGA package, however, is composed of conductive copper and surface-processed nickel, a fact that results in a constant voltage between the semiconductor chip 1101 and the heat spreader 1110 during the operation of the semiconductor chip 1101 and can cause damage to the semiconductor chip 1101 in many cases. Consequently, the semiconductor device yield of the conventional BGA package decreases, and the reliability of the semiconductor device may not be ensured when mounting the semiconductor chip on the printed circuit board.
Embodiments of the invention address these and other limitations of conventional devices.